Follow-ups of merged PRs

[smelc]

Changelog

- description: |
    Enhancements mentioned by @Jimbo4350 after he returned from vacation
# uncomment types applicable to the change:
  type:
  # - feature        # introduces a new feature
  # - breaking       # the API has changed in a breaking way
  # - compatible     # the API has changed but is non-breaking
  # - optimisation   # measurable performance improvements
  - improvement    # QoL changes e.g. refactoring
  # - bugfix         # fixes a defect
  - test           # fixes/modifies tests
  # - maintenance    # not directly related to the code
  # - release        # related to a new release preparation
  - documentation  # change in code docs, haddocks...

Context

• create-testnet-data: fix computation of not-delegated amount #638 (review)
• proposal: disambiguate binary data from text data #669 (comment)

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• Self-reviewed the diff